Modelling the impacts of climate change on soil carbon in pastures of western Victoria

Increasing soil carbon stocks is an often mentioned agricultural mitigation option. However, increasing carbon stocks in Australian soils is difficult given the highly variable climate, and the feasibility of increasing soil carbon stocks as the climate changes is uncertain. In this presentation the results of a modelling study addressing the potential impacts of climate change on carbon stocks in pastures of western Victoria will be discussed. Implications for sustainable stocking densities and the various sources of uncertainty in the response including climate and soil modelling uncertainty will be addressed.

Rachelle graduated with a bachelor's in wildlife biology from the University of Montana and an M.S. from the University of Melbourne. She worked for the United States Forest Service for the following 8 years, writing syntheses addressing fire ecology of plant and animal species. While there she devoted increasingly more time to local sustainability efforts and sustainability research, including investigating barriers to implementation of energy efficiency measures in the Forest Service. She is primarily interested in climate change issues that incorporate both natural and human systems and their interactions.

PhD Project: Integrated analysis of the mitigative and adaptive potential of soil carbon in grazing systems

Rachelle’s thesis uses a whole-farm system modelling approach to quantify the agro-ecosystem benefits and mitigation implications of soil carbon in the grazing systems of western Victoria in both recent and future climates. The primary research questions are:

What are the productivity benefits of greater N supply from mineralization and increases in plant available water holding capacity associated with increased SOM?

How much does increased soil carbon in a grazing system influence its sink potential and net emissions?

How do future climate projections affect the productivity benefits and GHG emissions associated with higher SOM at a local level?

What are the regional-level adaptation and emission consequences of increased SOM?

Comparing historic and future climates as well as local and regional scales will assist in identifying the potential for synergies or trade-offs of using soil carbon (in the form of SOM) as an adaptation and/or mitigation option. This research will also inform future local and regional scale investigations of potential adaptation-mitigation synergies.